postgres_ext.diff

diff --git a/config/initializers/postgres_ext.rb b/config/initializers/postgres_ext.rb
new file mode 100644
index 0000000..8b49f77
--- /dev/null
+++ b/config/initializers/postgres_ext.rb
@@ -0,0 +1 @@
+require './lib/postgres_ext/postgres_ext'
diff --git a/lib/postgres_ext/postgres_ext.rb b/lib/postgres_ext/postgres_ext.rb
new file mode 100644
index 0000000..c4957a6
--- /dev/null
+++ b/lib/postgres_ext/postgres_ext.rb
@@ -0,0 +1,7 @@
+require_relative 'postgres_ext/active_record'
+require_relative 'postgres_ext/arel'
diff --git a/lib/postgres_ext/postgres_ext/active_record.rb b/lib/postgres_ext/postgres_ext/active_record.rb
new file mode 100644
index 0000000..5d0c2f2
--- /dev/null
+++ b/lib/postgres_ext/postgres_ext/active_record.rb
@@ -0,0 +1,7 @@
+require 'active_record'
+require_relative 'active_record/relation'
diff --git a/lib/postgres_ext/postgres_ext/active_record/relation.rb b/lib/postgres_ext/postgres_ext/active_record/relation.rb
new file mode 100644
index 0000000..3bef1d5
--- /dev/null
+++ b/lib/postgres_ext/postgres_ext/active_record/relation.rb
@@ -0,0 +1,6 @@
+require_relative 'relation/query_methods'
diff --git a/lib/postgres_ext/postgres_ext/active_record/relation/query_methods.rb b/lib/postgres_ext/postgres_ext/active_record/relation/query_methods.rb
new file mode 100644
index 0000000..818f943
--- /dev/null
+++ b/lib/postgres_ext/postgres_ext/active_record/relation/query_methods.rb
@@ -0,0 +1,32 @@
+module ActiveRecord
+  module QueryMethods
+    class WhereChain
+      def overlap(opts, *rest)
+        substitute_comparisons(opts, rest, Arel::Nodes::Overlap, 'overlap')
+      end
+
+      private
+
+      def build_where_chain(opts, rest, &block)
+        where_value = @scope.send(:build_where, opts, rest).map(&block)
+        @scope.where_values += where_value
+        @scope
+      end
+
+      def substitute_comparisons(opts, rest, arel_node_class, method)
+        build_where_chain(opts, rest) do |rel|
+          case rel
+          when Arel::Nodes::In, Arel::Nodes::Equality
+            arel_node_class.new(rel.left, rel.right)
+          else
+            raise ArgumentError, "Invalid argument for .where.#{method}(), got #{rel.class}"
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/lib/postgres_ext/postgres_ext/arel.rb b/lib/postgres_ext/postgres_ext/arel.rb
new file mode 100644
index 0000000..1e57b3e
--- /dev/null
+++ b/lib/postgres_ext/postgres_ext/arel.rb
@@ -0,0 +1,8 @@
+require_relative 'arel/nodes'
+require_relative 'arel/predications'
+require_relative 'arel/visitors'
diff --git a/lib/postgres_ext/postgres_ext/arel/nodes.rb b/lib/postgres_ext/postgres_ext/arel/nodes.rb
new file mode 100644
index 0000000..afd3540
--- /dev/null
+++ b/lib/postgres_ext/postgres_ext/arel/nodes.rb
@@ -0,0 +1,6 @@
+require_relative 'nodes/array_nodes'
diff --git a/lib/postgres_ext/postgres_ext/arel/nodes/array_nodes.rb b/lib/postgres_ext/postgres_ext/arel/nodes/array_nodes.rb
new file mode 100644
index 0000000..70cf563
--- /dev/null
+++ b/lib/postgres_ext/postgres_ext/arel/nodes/array_nodes.rb
@@ -0,0 +1,14 @@
+require 'arel/nodes/binary'
+
+module Arel
+  module Nodes
+    class Overlap < Arel::Nodes::Binary
+      def operator; '&&' end
+    end
+  end
+end
diff --git a/lib/postgres_ext/postgres_ext/arel/predications.rb b/lib/postgres_ext/postgres_ext/arel/predications.rb
new file mode 100644
index 0000000..c93df32
--- /dev/null
+++ b/lib/postgres_ext/postgres_ext/arel/predications.rb
@@ -0,0 +1,14 @@
+require 'arel/predications'
+
+module Arel
+  module Predications
+    def overlap(other)
+      Nodes::Overlap.new self, other
+    end
+  end
+end
diff --git a/lib/postgres_ext/postgres_ext/arel/visitors.rb b/lib/postgres_ext/postgres_ext/arel/visitors.rb
new file mode 100644
index 0000000..6ec0e79
--- /dev/null
+++ b/lib/postgres_ext/postgres_ext/arel/visitors.rb
@@ -0,0 +1,6 @@
+require_relative 'visitors/postgresql'
diff --git a/lib/postgres_ext/postgres_ext/arel/visitors/postgresql.rb b/lib/postgres_ext/postgres_ext/arel/visitors/postgresql.rb
new file mode 100644
index 0000000..a39de8e
--- /dev/null
+++ b/lib/postgres_ext/postgres_ext/arel/visitors/postgresql.rb
@@ -0,0 +1,27 @@
+require 'arel/visitors/postgresql'
+
+module Arel
+  module Visitors
+    class PostgreSQL
+      private
+
+      def visit_Array o, a
+        column = a.relation.engine.connection.schema_cache.columns(a.relation.name).find { |col| col.name == a.name.to_s } if a
+        if column && column.respond_to?(:array) && column.array
+          quoted o, a
+        else
+          o.empty? ? 'NULL' : o.map { |x| visit x }.join(', ')
+        end
+      end
+
+      def visit_Arel_Nodes_Overlap o, a = nil
+        "#{visit o.left, a} && #{visit o.right, o.left}"
+      end
+    end
+  end
+end